JBCS

GC x GC color plot of a Brazilian base wine obtained with a polar and a medium-polar column set.

Metal halide hydrates are efficient catalysts to the Conjugate Friedel-Crafts reaction (CFC) of Indoles and activated olefins in alcoholic media. Solvent-free conditions were successful applied to prepare nitro-adducts and b-carbolines in good yields in an environmentally-friend protocol.

QSAR based on 2D chemical images (MIA-QSAR) shows that bidimensional structures correlate with biological activities, and is a promising tool for the design of new antimalarial compounds, with modeling capability comparable to well established 3D approaches.

The fatty acid methyl esters (FAME) were prepared by methylation of the total lipids (TL) and separated by gas chromatography using as parameter the equivalent chain-length values (ECL) in the identification and flame Ionization detector response factors in the quantification.

Figure A shows a regular oscillator being translating gradually into a non-equilibrium stationary state. Figure B shows a bifurcation point.

SWV optimized responses for different MP concentrations in supporting electrolyte 0.20 mol L^-1 acetate buffer pH 5.2 and volume of graphite suspension as a modifier of 10 mL. Inset: calibration curve for MP.

The complexes [VO₂(L)] and [VO₂(HLox)] were synthesized by the reaction of [VO(acac)₂] with the ligands HL and H₂Lox, respectively. Alternatively, [VO₂(HLox)] was also obtained by the reaction of HL with [VO(acac)₂] and hydroxylamine, or reacting [VO₂(L)] with hydroxylamine.

In the GA we are showing the EPR line variation with temperature of single-crystal [Cu₂(flu)₄(dmf)₂] compound and magnetic susceptibility versus temperature extracted from this measurements.

A procedure based on solid phase extraction with a strongly acidic cation-exchanger Dowex 50Wx
8-200 was proposed to pre-concentrate and determine ultra-traces of Li in floral honeys. It enabled to determine from 0.4 to 5.3 ng g^-1 of Li with precision being within 8-11%.

The Catalan solvent parameters were used to develop a new set of solute parameters. The developed solute parameters were used to propose a novel model for predicting aqueous solubility of solutes. The Catalan solvent parameters were employed to develop models for representing a number of physico-chemical properties of the solvents.

The electrochemical oxidation of a series of caffeic and ferulic acids derivatives as well as their corresponding redox moieties catechol and guaiacol was studied as a function of the structure in aprotic medium.

Upper Figure: Saturation of a liposome ¹H NMR signal transferred to the complex liposome-homoserine lactone (HSL)and dissociation produce free homoserine lactone with saturated hydrogens. Lower Figure: First binding events of the quorum sensing phenomenum showing the HSL diffusing through the bacterium membrane.

In the course of the coulometric determinations of acids (bases) in non-aqueous solvents (AN and PN), the electrochemical generation of lyate (hydrogen) ions is performed by the reduction (oxidation) of an appropriate electroreactive compounds. The natural minerals pyrite (FeS₂) and chalcopyrite (CuFeS₂) have been used as the indicator electrodes.

This image shows UV-Vis spectra and the present total color removal after 120 min of the 1.0 x10^-5 mol L^-1 basic red solution when treated by photoelectrocatalytic oxidation using both systems of irradiation (visible and ultraviolet) obtained before and after 120 min.

Low-cost portable microcontrolled nephelometer. a) Picture of the nephelometer developed; b) Schematic diagram of the optical compartment showing the blue LED and photodiode TSLB257 at 90º and infrared LED and TSL260R-LF at 90º.

In this article we demonstrate how to use an inexpensive instrumentation based on visible-high intensity LED and microscope for the determination of the electroosmotic flow in microseparation devices.

Morphology of Ocotea morae (Lauraceae) and structural formulas of major constituents from leaves (b-pinene), bark (1,8-cineole) and wood [(E)-nerolidol] essential oils.

We demonstrate the fabrication of nanosize poly(3-methyl thiophene) (P3MT)/ multiwalled carbon nanotubes (MWCNTs) modified glassy carbon (GCE) electrode for the sensitive determination of some common pesticides.

Two possible mechanisms for the 1,4-asymmetric induction in the stereoselective addition of (R)-pantolactone to 2-phenylpropylketene.

Voltammograms and the analytical curve obtained at glassy carbon electrode in 0.1 mol L^-1 phosphate buffer solution, pH 8.0 obtained at glassy carbon electrode for blank and fluconazole solutions.

Trend of the concentrations of Mg, Ca, P and organic matter in archaeological black earth (ABE) at the site Ilha de Terra from Caxiuana suggests placeholders as cemetery, religious ceremonies and food preparations by ancient inhabitants of this site.

Organic dyes comprising carbazole, iminodibenzyl and phenothiazine moieties, respectively, as the electron donors and di-anchoring rhodanine rings as the electron acceptors are synthesized and evaluated for use in dye-sensitized solar cells. Solar cells employing these organic dyes show good overall conversion efficiency (up to 4.91%).

Exhausted yerba mate leaves (Ilex paraguariensis) demonstrated to effectively adsorb metals from aqueous solutions, such as Cr(VI), which suggest the applicability of this cost effective biosorbent.

In this reaction substituted phenazines are formed by the neat reaction of alkylamines with lapachol, and in the figure the nitrogens are painted in blue to emphazise that one of the ring is originated from a Strecker degradation reaction.

Direct infusion ESI-MS/MS in the negative ion mode using SRM (m/z 124 -> m/z 80) was applied with high confidence, speed and selectivity to quantifty taurine in energetic drinks.